Abstract: Recent studies have clearly indicated that a significant proportion of bariatric surgery patients experience substantial weight regain and struggle with depression following their surgery. Understanding the mechanisms that contribute to these negative clinical outcomes is of considerable scientific and clinical importance. In the present study, we propose a model of predictors that we believe result in weight regain and depression. We will test the idea that in the moment, stress and negative affect predict loss of control eating, and that over time, loss of control eating predicts weight regain and depression in these patients. We will also investigate the influence of disinhibition on these relationships. Furthermore, we will use contemporary ecological momentary assessment and ambulatory assessment techniques to measure these variables and study their relationship to weight regain and depression in a prospective, longitudinal design. Finally, we will longitudinally examine weight regain and depression following bariatric surgery to clarify the temporal relationship between these variables.